1.首先删除redhat原有的yum ，因为redhat 原本的yum 没有注册为redhat用户是用不了的。
rpm -aq|grep yum|xargs rpm -e --nodeps
2下载163的yum 安装包
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/python-iniparse-0.4-9.el7.noarch.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-3.4.3-118.el7.centos.noarch.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-24.el7.noarch.rpm
3.进行安装yum
rpm -ivh python-iniparse-0.4-9.el7.noarch.rpm
rpm -ivh yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
rpm -ivh yum-3.4.3-118.el7.centos.noarch.rpm yum-plugin-fastestmirror-1.1.31-24.el7.noarch.rpm
注意最后两个包必需同时安装，否则会相互依赖
4.更新repo文件
mv /etc/yum.repos.d/rhel-debuginfo.repo /etc/yum.repos.d/rhel-debuginfo.repo.repo.bak
如果没有这个文件就直接创建
sudo nano /etc/yum.repos.d/rhel-debuginfo.repo
在文件中写入
[base]
name=CentOS-$releasever - Base
baseurl=http://mirrors.163.com/centos/7/os/$basearch/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/7/os/x86_64/RPM-GPG-KEY-CentOS-7
#released updates
[updates]
name=CentOS-$releasever - Updates
baseurl=http://mirrors.163.com/centos/7/updates/$basearch/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/7/os/x86_64/RPM-GPG-KEY-CentOS-7
[extras]
name=CentOS-$releasever - Extras
baseurl=http://mirrors.163.com/centos/7/extras//$basearch/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/7/os/x86_64/RPM-GPG-KEY-CentOS-7
[centosplus]
name=CentOS-$releasever - Plus
baseurl=http://mirrors.163.com/centos/7/centosplus//$basearch/
gpgcheck=1
enabled=0
保存退出
5 yum clean all
6 yum update 测试。
7 安装 epel 源
sudo yum install epel-release
如果不行就手动下载安装
wget https://dl.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-5.noarch.rpm
sudo yum install epel-release-7-5.noarch.rpm
$ sudo yum repolist检查是否安装成功